This invention relates to baffles for use in containers used for mixing of fluids, especially where at least one of the fluids is a liquid.
The use of rotating mixers in containers, especially cylindrical tanks, in the absence of some sort of baffle, results in a swirling motion of liquid within the container. Such swirling motion is generally laminar in nature, possessing none of the turbulent flow characteristics required for mixing low-viscosity fluids. The swirling motion also possesses very little vertical movement of the fluid which is necessary for effective mixing.
It is known that baffles, placed within the container, so as to disrupt the swirling motion, creates a turbulence which greatly improves mixing efficiency. Such baffles are usually elongated flat plates placed so that their longitudinal axis is parallel to the tank wall and so that the width of the plate rests on a tank diameter. The baffle is usually slightly offset from the tank wall to prevent accumulation of material at a baffle-tank wall interface.
It has been generally believed that four, rectangular, side-wall mounted baffles are the most effective baffle system available. Such baffles are not, however, suitable for use in vessels which are lined with a corrosion resistant material, such as glass plastic or some chemically resistant alloys, since they cannot be easily attached to the tank sidewall for support without creating a breach in the corrosion resistant lining. Further, the configuration of such rectangular baffles are not generally suited for lining with a corrosion resistant layer because of severe angles associated with a four sided plate.
It has been known to suspend corrosion resistant, e.g. glass lined, baffles, either from the top or bottom of a tank. Such baffles must thus be sized to fit through an access hole in the tank. Known baffles, including fin type baffles and rectangular baffles are not as efficient as desired for that purpose. Further rectangular baffles are not suitable for suspension, since the width of the baffle is restricted by the size of the access hole. Further for suspension of four rectangular baffles proximate four sidewalls, four access holes would be needed.